Prevention of foaming of hydrocarbon oils



Patent ed Feb. 25,- 1941 omit-1o STATE 5 ores PREVENTION OF FOAMING OFHYDROCARBON OILS Delaware No Drawing. Application January 3, 1945,Serial No. 571,198

13 Claims. 1

This invention relates to the prevention of foaming of hydrocarbon oils,particularly mineral oils and lubricants containing them.

This application is a continuation-in-part of our co-pendingapplication, Serial Number 478,- 154, filed on March 5, 1943, forPrevention of foaming of hydrocarbon oils.

Hydrocarbon oils and oil compositions containing them tend to roam orfroth when agitated in the presence of gases or vapors, such as air,steam, oil vapor, products of combustion, and the like.- The amount offoam or froth varies with the conditions under which the oilcompositions are agitated, as well as the character of the composition.Under some conditions, the volume of foam or froth produced is manytimes that of the original oil, and even with mild agitation,substantial amounts 'of foam are produced in many oil compositions. Inpreparing and using such oils and oil compositions commercially, theyare subjected to agitation under a wide range of conditions andfrequently undesirable amounts of foam or froth are produced.

Various means of combating such foaming of oils and oil compositionshave been proposed. For instance, mechanical devices have been proposedfor destroying or breaking foam as it is formed. Usually such deviceshave been cumbersome or inefiicient, or both, and they are not generallyused commercially. Likewise, the incorporation of certain oil-solublecompounds in the oil has been proposed as a means for preventingfoaming; such compounds being called "anti-foam agents. Unfortunately,no agent of this type has been found which is completely satisfactory incommercial practice; and their efiectiveness sometimes diminishesrapidly in use or they must be added to the oil in such amounts that thedesirable properties of the oil are impaired, or they are objectionablefor other reasons.

Among the objects achieved by this invention is the provision of animproved method of preventing foaming of hydrocarbon oils, particularlymineral oils and oil compositions containing them, in which the normalfoaming tendency of the oil is effectively abated or suppressed for longperiods of use without deleteriously affecting the other properties ofthe oil.

Another object achieved by the present invention is the provision of newand improved antifoam agents and compositions capable of abating andinhibiting foaming of hydrocarbon oils and oil compositions whendispersed therein in minute amounts.

A further object achieved by the present invention is the provision ofnew and improved oil compositions, particularly improved mineral oilsand lubricants, having marked resistance to foaming and otheradvantageous properties including resistance to emulsification andcontaining minute amounts of an oil-insoluble antifoam agent finelydispersed therein.

We have discovered that foaming of hydrocarbon oils, particularlymineral oils and compositions containing them, can be effectivelysuppressed or prevented without substantial modification of thedesirable properties of such oils by forming in the oil a stable, finedispersion of a small amount of a substantially oil-insoluble liquidcondensation product of an organo-silicon oxide compound having a lowinterfacial tension toward the oil. We have found that hydrocarbon oilcompositions containing such liquid organo-silicon oxide condensationproducts as a stable, finely dispersed phase are markedly resistant tofoaming even under the most violent conditions encountered in commercialpractice. The presence of the finely dispersed insoluble liquid phase inthe oil apparently causes the films of the oil foam to rupture, therebyquickly destroying the foam. In fact, in most cases, its presence sorapidly breaks the oil foam that substantially all foam is destroyed asfast as it is formed.

In the practice of this invention, various oilinsoluble liquidorgano-silicon oxide condensation products having a low interfacialtension toward oil and capable of being stably and finely dispersed inthe oil may be employed as antifoam agents. These oil-insoluble liquidorganosilicon oxide condensation or polymerization products possess theproperty of a low interfacial tension toward hydrocarbon oils in markeddegree, and are particularly advantageous for the purpose of ourinvention because they are capable of being stably and finely dispersedin such oils. The interfacial tension of such liquid organosilicon oxidecondensation products toward hydrocarbon oils can be measured on aspecial type DuNouy tensiometer. The condensation products having lowtensions have proved most useful as foam suppressing agents.

The organo-silicon oxidecondensation products contemplated for useaccording to this invention are composed primarily of a plurality ofsilicon atoms linked together through oxygen atoms, each silicon atomhaving attached to it at least one organic radical either directly orthrough an oxygen atom, and they may contain condensation products whichhave been found suitable for the purposes of our invention include forexample the liquid organo-siloxanes and the liquid organo-silicatecondensation products.

The organo-siloxanes are sometimes referred to is the organo-siliconepolymers or condensation products as a result of the fact that they areprincipally composed of organo-silicone residues. They vary incomposition depending upon the materials from which they are producedand the method of production. They are usually produced as condensationor polymerization products -of the organo-silicols including themono-sillcols, disilicols and trisiiicols and mixtures of thesesilicols. The organo-silicone residues from these three'silicols are ofthree different types. The silicone residue of the monosilicols may berepresented generically by the formula i s it a" 1-0- in which R, R orR" represent similar or dissimilar organic radicals such as alkyl, aryl,aralkyl, alkaryl or heterocyclic groups. The silicone -resldue of thedisilicols may be represented generically by the formula sir-@- in whichR and R represent similar or dissimilar organic radicals such as alkyl,aryl, aralkyl, alkaryl or heterocyclic groups. The silicone residue ofthe trisiiicols may berepresented by the formula in which R representsan organic radical such as an alkyl, aryl, aralkyl, alkaryl orheterocyclic group.

The organo-siloxanes or organo-silicone condensation products maycontain any one or all three of the above types of silicone residuesdepending upon whether they, are produced from pure silicols or mixturesof two or three of the mono-, diand trisiiicols. The condensationproducts obtainable may be straight chain, cyclic a a w-i-o-Jx-rv inwhich R, R' and. R" represent similar or disalkaryl, aralkyl andheterocyclic groups. These compounds are generally liquid and areefl'ective anti-foam agents. They are, however, somewhat soluble inhydrocarbon oil compositions and are for this reason somewhat lesseffective than other organo-siloxanes. However, the condensationproducts of organo-mono-silicols in admixture with diols and triols areparticularly valuable aeiat'os 4 for the purposes of our invention. Thepresence of mono-silicols tends to prevent excessive formation ofresinous solids rather than liquid condensation products.

The oily liquid condensation products obtained by polymerization oforgano-silane diols are particularly advantageous anti-foam agents forthe present purposes. The organo-disilicol compounds when polymerizedalone tend to produce predominantly straight chain polymerizationproducts which may be generically represented by the following formula:

, wherein R represents an organic radical, such as similar organicradicals such as alkyl, aryl,

alkyl, aryl, aralkyl, alkaryl or heterocyclic group, R is a similar ordissimilar organic radical and 11 may be one or higher depending uponthe number of organo-silicon oxide residues in the complex moleculeresulting from the condensation and dehydration of the organo-silan'ediol.

When the organo-silane diols are polymerized in the presence of anorgano-silane-mon'ol the monol tends to substitute at the end of thechain in place of at least one hydroxyl group and produce compoundshaving the formula in which R, R and R" represent similar or dissimilarorganic radicals such as the alkyl, aryl, aralkyl, alkaryl orheterocyclic group, X may be such an organic radical or a hydroxyl groupand n may be one or higher. Similarly other terminal groups may besubstituted in these compounds in which case the generic structuralformula may be represented by {LOPLY it n 11'.

there may be obtained suitable oil insoluble liquid condensationproducts containing for example cross polymerization products having aformula of the following type:

in which R, R and R." may be similar or dissimilar alkyl, aryl, aralkyl,alkaryl or heterocyclic group and n may be one or more. It will beunderstood that this formula is merely illustrative of crosspolymerization products suitable for the purposes of our invention andsuch products may take other forms in which two or more cross linkingsbetween polymers are established. Such compounds may take a form inwhich they resemble cyclic compounds for example:

the liquid condensation products particularly effective. These viscousoily liquids, in general, have low surface tensions and low interracialtensions toward hydrocarbon oils. They also have low solubility inhydrocarbon oils and are readily dispersible in such oils, particularlymineral lubricating oils. In general, we find the condensation productscontaining simple organic radicals, such as methyl, ethyl andshort-chain alkyl groups, most advantageous for the purposes of ourinvention, as they have exceedingly small solubility in most hydrocarbonoils.

For example, we have found that the .oily liquid condensation productsof the methyl silicols are, in general, good anti-foam agents. Theliquid condensation products of di-methyl-silane diol are mostadvantageous for this purpose, :However, very good results have alsobeen obtained from condensation products of mixtures containingtri-methyl-silane monol, di-methyl-silane diol and methyl-silane triol.Dimethyl-silane diol has the following formula:

HO-Si-OH It is customarily produced from silicon tetrachloride throughthe Grignard reaction as follows:

CH: Cl

2CH;MgBr BiCli $1 (MgBr MgCi CH: Cl

CHI Cl OH: OH

Bi 1120 Si 21101 CH: 01 C 3 0H In this reaction all of the silicontetrachloride may not be converted to the di-methyl-silane diol,- Theproduct may then consist of a mixture of tri-methyl-silane monol,di-methyl-silane diol and methyl-silane triol. may be polymerizeddirectly to produce satisfactory antifoam agents for the purpose of ourinvention. Alternatively, intermediate separation may be effected sothat polymers of the individual silicols may be produced.

As a class, these liquid condensation products are for all practicalpurposes substantially oilinsoluble. They are also substantiallyinsoluble This reaction product in water and aqueous solutions. On theother hand, they can be readily dispersed in hydrocar-' bon oils to formstable dispersions containing extremely fine particles ofoil-insolubleliquid. In fact, we have prepared oil compositions containing suchoil-insoluble liquids dispersed therein, in which the majority of thedispe sed pa e range from 2.0 to 0.3 microns or less. Such finedispersions of these condensation products in oils are very stable andare markedly resistant to foaming. Oil compositions containing from 5 toparts per million of these compounds finely dispersed therein yieldlittle or 'no foam when subjected to drastic foaming tests. In fact,compositions containing as low as 0.05 part per million of a dispersedsiloxane condensation product showed a measurable resistance to foaming.

The liquid condensation products of the methyl-silicols described aboveare merely illustrative of this type of anti-foam agent. The liquidcondensation products of other organosilicols are also effective insuppressing foaming of hydrocarbon oils and may be employed as theanti-foam agent. The amount used should be sufficiently in excess of thesolubility of the compounds in the oil to give the required amount ofdispersed liquid phase necessary to prevent foaming under serviceconditions. For this reason, the liquid siloxanes which aresubstantially oilinsoluble are most advantageous. While we have foundthat the compounds containing the simple organic radicals, such asmethyl, ethyl and shortchain alkyl groups, are especially advantageousfor the present purposes, satisfactory results can also be obtained withorgano-siloxanes containing other organic radicals, such for example asaryl siloxanes, alkaryl siloxanes and substituted aryl siloxanes.Diphenyl siloxanes have produced particularly. good results, and goodanti-foam properties have also been obtained with condensation productssuch as methyl phenyl siloxanes and di-chlorphenyl siloxane.

Another class of liquid organo-silicon oxide condensation products whichwe have found useful as foam inhibitors includes the organo-silicatecondensation products represented by the probable formula:

t on

OK it in which R represents an organic radical such as an alkyl, aryl,aralkyl, alkaryl or a heterocyclic group and 12. may be one or higherdepending upon the number of organo-silicate residues in the complexmolecule of the condensation product.

These compounds may be obtained as the polymerized hydrolysis productsof the esters of ortho silicic acid by controlled hydrolysis of thetetra orthosilicate esters with water. Hydrolysis and condensation orpolymerization take place simultaneously with the formation of liquidproducts which are in general substantially insoluble in hydrocarbonoils and have little or no interfacial tension toward such oils.Normally mixtures of products in various degrees of polymerization arefirst obtained. These mixtures may be used directly as anti-foam agents.It is generally more advantageous, however, to isolate the higher liquidpolymerization products from the total products. We have found that theefiectiveness z '7 of these organo-silicate condensation products inpreventing foam formation increases with in-- creased molecular weightand boiling point, Also,

the higher condensation products are less solu-,.

ble in the hydrocarbon oils. Consequently, we find it advantageous touse'the higher boiling liquid.fractions of the products. Separation ofthe desired fractions may be accomplished by vacuum distillation of thetotal reaction products."

formation, without deleteriously modifying the advantageous propertiesof the oil. In general,

-- we find the organo-silicate condensation products containing simpleorganic radicals, such as methyl, ethyl andshort-chain alkvl groups mostadvantageous as they have exceedingly small solubility inmosthydrocarbon oils. For example, we have found that, a fraction of thetotal reactionproducts obtained on hydrolysis and polymerization oftetramethyl orthosilicate and fractionation at 220 to 240 C. at0.75,mm.,

which consists predominantly of a condensation productin" which n is ofthe order of 3, is mark-' edly effective in concentrations as low as 0.1per cent and less. A similar fraction obtained by hydrolysis andpolymerization of tetraethyl orthosilicate and fractionation of theproducts to recover the compounds boiling above 290 C. at 1 mm., provedeflfective in concentrations as low as 0.005 per cent and less.

The particle size of the insoluble liquid dispersed in the hydrocarbonoil has a marked effect upon the resistance to foaming so imparted tothe oil compositions. In general, we have found that oil compositionscontaining dispersions of our new oil-insoluble, anti-foam agents inwhich the liquid particles are about 2.0 microns and less in size areparticularly advantageous for the present purposes. Such oilcompositions are very stable in storage and under service conditions,and they have a, high resistance to foaming which they retain over longperiods of use.

Further, since good resistance to foaming can be readily obtained withexceedingly small proportions of our new anti-foam agents finelydispersed in the hydrocarbon oil, the anti-foam agents of our inventiondo not deleteriously modify the other properties of such compositions.

Accordingly, the desired foam resisting properties can be imparted tosuch oils without impairing their effectiveness as lubricants or forother intended uses.

In the commercial practice of this invention, oil compositions may beproduced directly in which the anti-foam agent is present in the desiredsmall amount and fine dispersion. However, in certain embodiments of theinvention, oil compositions initially containing relatively coarsedispersions and relatively high concentrations of the anti-foam agentsmay be first prepared and the desired finely dispersed agentconcentration may be produced in the hydrocarbon oil during use byagitation thereof in the lubrieating system, such as by gear pumps andother mechanisms Such production of the desired fine dispersions in situin the oil during use is sometimes advantageous. Of course, the amountof anti-foam agent and the fineness of the disable method capable ofproducing a stable fine j dispersion of the liquid agent in the oil. For

example, the anti-foam agent may be dissolved in a light hydrocarbon orother suitable solvent, such as mineral seal oil, gasoline, naphtha,hexane and benzene, and this solution may be introduced into thehydrocarbon oil to whichit is desired to give anti-foam properties. Theantifoam agents of our invention are substantially soluble in thesesolvents at normal temperatures, and after such a solution has beenformed it may be incorporated in the hydrocarbon oil or oil compositionor crude oil, simply by mixing and agitating the solution therewith. Afine dispersion of the anti-foam agent in the oil is thus obtained. Aconvenient solution for such use would contain 1.0 per cent of activeanti-foam agent. To add 0.001 per cent anti-foam agent to the final 'oilwould require the addition of 0.1 per cent of the solution of anti-foamagent. .Where it is desired to form directly a dispersion of theantifoam agent in the oil, various commercial colloid mills may beemployed to disperse finely the liquid agent in the oil. In this way,stable fine dispersions, wherein the size of the dispersed liquidparticles is within the range of 2.0 to 0.3 microns or less, are readilyobtained. Also, gear pumps may be employed to disperse the liquidanti-foam agent in the oil. The use of such gear pumps is advantageousin many embodiments of this invention, particularly those wherein finedispersions of the anti-foam agents are produced in situ in the oil.Other methods and apparatus may also be employed in dispersing theseagents in oils or oil compositions.

It is sometimes advantageous to first disperse the liquid anti-foamagent in part Of the oil and then add this concentrate dispersion to theremainder of the oil. Such concentrate dispersions can be readilyprepared as stable uniform compositions. For instance, a mixture of oiland antifoam agent in the desired proportions may be continuouslycirculated through a gear pump until a stable concentrate containing auniform dispersion of the agent in the desired particle size isobtained. Thus, standardized concentrates can be prepared which can beadded to lubricating compositions as needed. In such case, the desiredamount of concentrate is added to the hydrocarbon oil composition andthe mixture is agitated until uniform.

Also, such concentrates are themselves valuable anti-foam compositions.As they contain a preformed, dispersed, insoluble liquid phase of thedesired particle size, they quickly break oil foams, as well as suppressfoaming in general. For instance, when added to oil or oil compositionswhich have foamed, they rapidly destroyed the foam present and stoppedfurther foaming. In such cases, they can be quickly blended with oils,oil compositions, and crude oil and uniformly incorporated thereinbefore'serious foaming occurs.

For such purposes, oil concentrates containing from to 2000 parts permillion of finely dispersed liquid organo-silicon oxide condensationproducts are advantageous. By adding from 0.1 to 10 parts of suchconcentrates to 100 parts of 9 minerallubricating oils, improvedlubricants havlng marked resistance to foaming are readily and easilyobtained.

One particularly advantageous field of use for the anti-foam agents ofour invention is in lubricents for internal combustion engines, such asautomotive, aviation, Diesel and like engines, because we have foundthat even under the high temperature of operation of these engines,these compounds retain their foam-inhibiting properties. In lubricatingsuch engines, appreciable foaming of the motor oil seriously interfereswith effective lubrication. For instance, aviation oils (either straightor compounded oils) tend to foam at the low barometric pressuresencountered at high altitudes. Also in lubricating such engines,particularly aviation engines, the lubricating oil is circulated underpressure through the parts to be lubricated. In doing so gear pumps areusually employed in supplying pressure 611 to the engine and returningthe oil from the engine sumps to the reservoir tank. In such systems,the scavenger pump is usually of such capacity as to maintain the enginesump in a substantially dry condition. With such dry sump systems, thescavenger pump frequently pumps large volumes of air with the oil, thisair becoming dispersed in the oil. Under such conditions, excessive foamoften leads to loss ofthe oil from the engines and impairs thelubrication. By the present invention, such foaming can be readilyovercome or suppressed. For example, an appropriate amount of our liquidanti-foam agents can be introduced into the circulating oil anddispersed therein by the gear pumps, or oil concentrates of theanti-foam agents can be intermittently injected into the oil anduniformly dispersed therein by such gear pumps whenever substantialamounts of foam appear in the system. Further, such foaming can beprevented and the engine eifectively lubricated at all times byemploying an improved lubricant containing these liquid anti-foam agentsdispersed therein from the beginning.

While our anti-foam agents and improved motor oils are particularlyadvantgeous in lubricating engines wherein the oil is circulated underpressure by means of such gear pumps, they are also useful andadvantageous in lubricating certain types of engines using splashlubrication. Also, modern Diesel engine oils usually contain relativelylarge amounts of additives of the detergent or detergent-dispersiontype. It has been found that such additives promote foaming.Accordingly, many Diesel oils foam badly. By the present invention, suchfoaming is effectively prevented and improved anti-foaming Diesel oilsreadily obtained.

Another advantageous field of use is in gear lubricants, particularlyfor transmission gears of automotive equipment and the like. Inlubricating such gears, the oil composition is violently agitated by therotating gears and substantial amounts of foam are formed. This foaminterferes with the lubrication and cooling of the gears. By the presentinvention, this foaming and its attendant difllculties in gearlubricants are effectively prevented and overcome.

Still another field of use for the products of our invention is in thelight oils used in steam turbines. With these light oils, agitation mayproduce considerable foaming. By the present invention, such foaming oflight oils is effectively prevented. Furthermore, there is often atendency for steam turbine oils to emulsify with the Venezuela.

water with which they are mixed. We have found that the anti-foam agentsof our invention have an additional advantage in this use, because theygenerally increase the resistance of such oils to emulsiflcation.

Our improved anti-foaming agents also may be advantageously added tocrude oil to prevent foaming in pipe lines, storage tanks and the like,particularly such oils as are produced in western Concentrations of theorder of 0.00005 per cent or 0.5 parts per million are quite eifectivein suppressing foaming in crude oils. It is usually advantageous to addthe anti-foam agent to the crude oil in solution in a solvent such asone of those indicated above, because of the small amount of anti-foamused in a large volume of crude. Good results can be obtained when theanti-foam agent is added to the crude oil when the crude oil is beingfed from the wellhead to a gas separator. The agitation secured at thispoint is sufficient for distributing the solution of anti-foam agentsthrough the crude oil. The effect of adding such solutions of ouranti-foam agents is that existing tankage and equipment for handlingsuch crudes can, for its capacity, about double its throughput. Our newanti-foam agents and compositions are also useful in other oilcompositions and effectively prevent the foaming thereof. Indeed, theyare useful and advantageous in any hydrocarbon oil or oil composition inwhich they are substantially insoluble whether used as a lubricant ornot, and in which it is desired to prevent foaming. However, they areparticularly effective in combating foaming in mineral lubricating oilsand lubricants.

The relative effectiveness of various organosilicon oxide anti-foamagents of our invention in preventing foaming in different hydrocarbonoils and oil compositions may be demonstrated by means of the followingfoaming test in which the oil or oil composition is controllably aeratedunder fixed conditions, so that the results obtained in a series oftests are directly comparable.

In carrying out this test, 200 cc. of the oil are placed. in a tallgraduate and air, in the form of line bubbles, is passed upwardlythrough this column of oil at a controlled rate of 0.2 cubic feet perhour by means of a diffuser positioned in the bottom of the graduate.The graduate is closed with a suitable cover provided with air inlet andoutlet tubes. The inlet tube extends to the bottom of the graduate andhas a diffuser fixedly mounted on the lower end. Air is passed downthrough this tube and through the fine pores of the diffuser into theoil. In this way. uniform fine air bubbles are introduced at the bottomof the oil column. The fine air bubbles pass up through the column ofoil agitating it and forming foam. The volume of foam formed at the topof the 011 column can be readily and accurately measured on thegraduate. V

By this test, the time to form a given amount of foam may be noted andrecorded and the amount of foam formed in a given time from the start ofair flow through the oil may be measured and recorded. Either of thesemeasurements gives a numerical value proportioned to the over allaverage rate of foaming. One or both of these values can be convenientlyused to compare and evaluate the respective foaming properties ofdifferent oils and oil compositions.

In the above test, the foaming characteristics of the oil or oilcomposition tested are usually determined at room temperature underatmospheric pressure. However, if desired, similar foaming tests can bemade at other temperatures test may be made at reduced pressures byconnecting the air outlet of the graduate to a suitable low pressurereservoir maintained at the pressure desired;

In the following specific examples, there are illustrated by means ofthis foaming test the advantageous-results obtained by incorporating inamineral lubricating oil the. organo-silicon oxide anti-foam agents ofour invention.

Exmnple I Oxygen, per- Carbon, Hydrogen Silicon percent percent percenthgi gg sac 8.15 30.5 24.35

It had a low interfacial tension toward the selected oil and waspractically insoluble although it was readily dispersible in theselected oil.

In dispersing this liquid anti-foam agent in the lubricating oil, aconcentrated oil dispersion was first prepared. In doing so, 0.1 part ofthe di-methyl silicon oxide compound was added to 99.9 parts of the oilby weight, and this mixture was continuously circulated through a gearpump until a fine dispersion containing dispersed liquid particlesvarying from less than 0.3 to 2.0 microns was obtained. Next, one partof this concentrate was added to 9.9 parts .of the selected paraflinic2. Base oil+l P. P. M. antiioam agent..

lubricating oiland this oil mixture was agitated with a suitable stirreruntil a uniform composition was obtained. The non-foaming lubricatingoil so obtained contained 10 parts of the liquid anti-foam agent permillion parts of oil. inspection properties of this improved non-foamingoil composition were substantially the same as those of thebase oil, asshown in the following table:

' Base oil-H0 Composition Base oil P. P. M. antii'oam agent Gravity, API29. 6 29. 6 Viscosity SUV et- 100 F l, 065 I, 081 210' Fns- 06. 4 97. 4go l or, NPAt" 3.. s rcen 0. 01 0.01 Predgftatlon No 0.05 0.05Neutralization N o 0.03 0.02

To compare the foaming properties of the base oil and the oil containingthe dimethyl silicon The- Time,

Composition mum 1. Base oil As shown by the above test, this oilcontaining the anti-foam agent of our invention is efiectively renderednon-foaming.

Example I! In this example a methyl siloxane product was produced fromsilicon tetrachloride and tested as an anti-foam agent.

The methyl silicone polymer was follows:

Silicon tetrachloride dissolved in an equal volume of ether was mixed ata temperature between 10 C. and 0 C. with methyl magnesium chloride inether in a ratio of one mol of silicon tetrachloride to each two mole ofmethyl magnesium chloride. Near the end of the mixing, the temperaturewas allowed to rise slowly until the ether refluxed gently. After allthe methyl magnesium chloride had been added, heat was applied and themixture was refluxed for one hour. hfter the reaction product stoodovernight, it was poured over cracked ice to hydrolyze the methylsilicon chlorides. The ether solution of the hydrolyzed reactionproducts was then washed with water and with sodium thiosulfatesolutionuntil neutral and until all of the free chlorine had beenremoved. The ether was then evaporated and the methyl silicoi productrecovered. No attempt. was made to recover the.

prepared as 9 N sulfuric acid was added. This mixture was heated on asteam bath for about five to ten minutes. After about two hours thebenzene layer was separated from the sulfuric acid, was washed withwater .and treated with small portions of activated charcoal on thesteam bath over a period of three-quarters of an hour. The activatedcharcoal was filtered off and the benzene was evaporated in about twohours by heating over a steam bath in a current of air. The last tracesoi benzene were removed under vacuum to recover the methyl siliconepolymerization products or methyl siloxanes;

' The methyl siloxane product on analysis gave the following results:

Percent Percent hydrogen silicon Percent carbon These results show ahigher silicon to carbon I Example III In this example methyl-o-silicatecondensation products were prepared by partial hydrolysis of tetramethyl-o-silicate, and were tested as antifoam agents.

The preparation of the methyl-o-silicate polymer or condensation productwas carried out as follows:

Freshly distilled tetra methyl-o-sil cate was mixed with alcoholcontaining about 4.5 per cent of water, in such proportion as to provideabout 0.8 mol of water per mol of silicate. The mixture was then heatedat refluxing temperature for two hours. The alcohol and unchanged tetramethyl orthosilicate were then distilled off at atmospheric pressure.The condensation products were then fractionallv distilled at 0.75 mm.pressure at temperatures between 120 and 240 C. The fractions boilingbetween 200 and 220 C., between 220 and 240 C. and the residue boilingabove 240 C. were tested as anti-foam agents. 3

The tests of the respective fractions as anti-foam agents were made incomparison with the uncondensed tetra methyl-o-silicate and with thecommercial dimethyl siioxane used above in Example I. The results ofthese tests are shown in the following table.

Percentage in base oil required for equivalent results Material testedDimeth l siloxane y Not effective Teiramethyl-o-silicaie. .L Silicatecondensation product B.

mm 0.25 Silicate condensation product B. P. 220240 C./0.75

mm 0.1 to 0. 25 Silicate condensation product B. I. above 240 C./

These results indicate that the higher boiling liquid methylorthosilicate polymers are the more effective anti-foam agents but thatthe methyl silicate polymers are substantially less effective than themethyl siloxanes as anti-foam agents.

Example IV mercial dimethyl siloxane described in Example I. Thefollowing results were obtained:

Percentage in base oil Material tested required [or equivalent resultsDimethyl siloxene 0. Tetra ethyl-o-silicate Not efiecm silicatecondensation product B mm l. Etiyl silicate condensation product B. P.280-290" 0 mm 0. 5 Ethyl silicate condensation product B P. above 290C./1 mm 0. 005

These results indicate also that the higher boiling fractions of theethyl-o-silicate condensation products are the more effective anti-foamagents.

While our invention has been described above with reference to variousspecific examples and embodiments, it will be understood that theinvention is not limited to such illustrative examples and embodiments,and may be variously practiced within the scope of the claims hereinmade.

What we claim is: a

1. A composition of matter of reduced foaming properties comprising anorganic liquid having foaming tendencies and a small amount, less than0.1 per cent, of an active defoaming compound comprising a dehydrationsilicon oxide condensation product.

2. The composition of claim 1 wherein said liquid is a hydrocarbon oil.

3. The composition of claim 1 wherein said liquid is a colloidaldispersion of an organic substance.

4. The composition of claim 1 wherein said active compound is insolubleand colloidally dispersed in said organic liquid.

5. The composition of claim 1 wherein the active compound is a liquid.

6. A heavy duty motor oil of improved antifoaming properties consistingessentially of a mineral lubricating oil and containing an active 1amount of a detergent tending to increase foaming and, colloidallydispersed, a small amount, less than 0.1 per cent, of an active defoamercomprising a dehydration silicon hydroxide condensation product.

'7. A process of suppressing foaming in hydrocarbon oils and hydrocarbonoil compositions which comprises producing in the oil a stable finedispersion of a liquid organo-silicon oxide condensation product in anamount corresponding to at least 0.5 parts per million of the oil butinsufiicient to substantially modify the desirable properties of theoil.

8. A process of suppressing foaming in hydrocarbon oils and hydrocarbonoil compositions which comprises producing in the oil a stable finedispersion of a liquid organo-silicon oxide condensation product in anamount corresponding to from 0.5 to parts per million of the oil.

9. A process as claimed in claim 8, wherein the dispersion of liquidorgano-silicon oxide condensation product comprises predominantlyparticles of 2.0 microns and less in size.

10. A process of suppressing foaming in hydrocarbon oils and oilcompositions containing them, comprising forming in said oil a. stablefine dispersion of a liquid organo-silicon oxide condensation producthaving a low interfaoial tension toward said oil in an amountcorresponding to at least 5 parts per million of said oil andinsufficient to deleteriously modify other desirable properties of theoil, by incorporating in said oil I a solution of said liquidorgano-silicon oxide condensation product in a lighter hydrocarbon thansaid oil in which said organo-silicon oxide condensation product issubstantially more soluble than in said oil, said solution containing100 to 2000 parts per million of said liquid organosilicon oxidecondensation product.-

11. A hydrocarbon oil composition of reduced foaming'pro'pertiescomprising a hydrocarbon oil having foaming tendencies and anorgano-silicon oxide condensation product stably dispersed in said oilin a small amount, not less than 0.5 parts per million, insufiicient tosubstantially modify the desirable properties of said oil.

12. A hydrocarbon oil composition of reduced foaming propertiescomprising a hydrocarbon oil having foaming tendencies and from 0.5 to100 parts per million of a liquid organo-silicon oxide condensationproduct stably dispersed in said 011.

13. A composition adapted to impart foamresisting properties tohydrocarbon oils and compositions containing them when added thereto inan amount corresponding to 0.1 to 100 parts per hundred, comprising ahydrocarbon liquid containing from 100 to 2000 parts per million of a.liquid organo-silicon oxide condensation Product.

CHARLES E. TRAUTMAN. HENRY A. AMBROSE.

REFERENCES The following references are of record in the file of thispatent:

UNITED STATES PATENTS OTHER REFERENCES Chemical & MetallurgicalEngineering, Aug.

1944, DD. 109 and 136. (Copy 1n Div. 50.)

Certificate of Correction Patent No. 2,416,503.

February 25, 1947 CHARLES E. TRAUTMAN ET AL.

It is hereby certified that errors appear in the printed specificationof the above numbered patent requiring correction as follows: Column 14,lines 31 and 48, for dehydration read dz'hydrocarbon; column 16, line16, for the patent number 2,345,155 read 2,346,155; and that the, saidLetters'Patent should be read with these corrections therein that thesame may conform to the record of the case in the Patent Oifice.

Signed and sealed this 29th day of April, A. D. 1947.

LESLIE F,

First Assistant Gammissioner of Patents.

